Floor-coverings with dense solid surfaces such as ceramic, wood, vinyl, rubber or urethane are generally durable, and can effectively contain liquid spills at or near the surface, but offer little or no cushion. These solid floor-coverings also lack the aesthetics and surface softness of textile/fibrous floor-coverings. Textile floor-coverings, on the other hand, lack the capability to contain liquid spills at the surface. In institutional applications, such as hospitals, office buildings, restaurants, schools, retirement homes and the like, it is highly desirable to combine the soft and cushioning surface of the textile floor-coverings with the superior spill-containing capability of solid floor-coverings. Additionally, the capability to resist the impact of liquids dropped from substantial heights such as 1 meter, and to hold the spills at the surface or within a very small depth beneath the surface, for long periods of time, to facilitate clean-up is also desirable.
FIG. 1 is a diagrammatic chart of the surface barrier and surface softness of various floor-coverings. Solid floor-coverings with superior barrier and hard surfaces are located at the lower right-hand corner of the chart. Textile faced floor-coverings with open, deep and soft cushioning face layers, such as pile structures, are located at the opposite upper-left hand corner. Desirable institutional floor-coverings, that would combine both of the attributes of superior barrier and soft surface, are assigned to the right hand upper corner.
The first and most common type of conventional textile floor-coverings, grouped at the upper left-hand corner of FIG. 1, provides cushion with a relatively deep, open, and soft textile face layer. The face layer preferably comprises a “pile” of upstanding yarns 31, secured by a primary backing 32, as shown in FIG. 2. The face layer is optionally treated with repellent finishes. Pile structures, and especially looped-yarn piles and relatively closely-spaced piles, can maintain their facial appearance better than “nonwoven” structures, wherein individual fibers oriented in all directions are subject to bending or deforming as they individually absorb stress during use. Yarns also offer color and design capabilities, especially with pigment-colored yarns that can resist chemical cleaning. Piles offer “face softness” which is low resistance to initial light compression. Light pressure depresses the area of contact making a temporary local indentation, without spreading the load sidewise or in the planar direction, as illustrated in FIG. 2. Unfortunately, the openness of the pile makes it incapable of blocking spills from propagating through depth 33 to the bottom 34, even when the piles are formed with repellent fibers or treated with repellent polymers. Especially spills that fall from higher heights, such as 40 inches or 1 meter, which can occur frequently, tend to follow the path of the yarns through and beyond primary backing 32, to the backlaps 35, and on towards the floor underneath, and to soak the primary backing. Pile carpets are very difficult to clean, and in situations where the spills involve decomposable organics such as food, blood or urine and the like, they create chronic odor problems. Spills that occur from smaller heights may temporarily stay above the face layer, allowing time for quick response to the spills, but within seconds or minutes break through to the bottom of the face layer, with or without subsequent surface contact such as light hand-patting or stepping on the spill. Furthermore, repellent treatments tend to wear out with traffic or multiple cleanings, further reducing the short time available to react to a spill. To protect the underlying floor liquid-blocking sub-layers have occasionally been added to the underside of formed carpets as disclosed in EP 0590422/B1 to Goss, U.S. Pat. No. 5,612,113 to Irwin, U.S. Pat. No. 7,247,352B2 to Jones Jr., U.S. Pat. No. 7,803,446 B2 to Martz, and EP 0963476 to Bieser, among others. Details of barrier performance are not discussed. EP 1112406B to Jenkines discloses aqueous polyurethane dispersions, applied to the backside of pile carpets, and designed to limit the propagation of spills that reach the bottom 34 of the pile.
As secondary protection for the floor, under-pads, variously called “carpet pad” or “carpet underlayment” or “carpet cushion”, are deployed under carpets or rugs, are optionally equipped with barrier layers. Examples of such under-pads are discussed in US 2006/0280902 to Otteson et al., U.S. Pat. No. 6,572,965B1 to McGee, U.S. Pat. No. 6,872,445 to Vinod, US 2004/0071927 to Murphy, CA 2,320,471 to Denney, U.S. Pat. No. 5,541,849 to Collins, EP 1907622A2 by Butenschoen, U.S. Pat. No. 7,279,058 to Morgan, EP 1232301 A1 to Huffines, U.S. Pat. No. 4,360,554 to Campbell, U.S. Pat. No. 5,032,705 to Rose and US 2009/0123688 by Miller, among many others. The under-pads only protect the floor underneath by not allowing the liquids which have already penetrated the whole overlaid floor-covering from reaching the floor. They do not provide a durable surface suitable to use directly as a floor-covering. In FIG. 1 they are also placed at the upper left hand corner.
In a second type of durable textile-faced floor-coverings, most or all of the cushion is provided by a low-bulk cushioning backing attached underneath a much thinner fibrous/textile face fabric. These floor-coverings can provide textile aesthetics, relative cushion and high durability if the face fabric itself is durable, and securely attached to the cushion to resist delamination. They generally do not offer spill-blocking resistance. Spills are likely to proceed into the deeper soft backing, and on to the floor underneath. They include U.S. Pat. No. 3,985,925 to Lefevbre, WO99/19557 to Scott, U.S. Pat. No. 2,688,578 to Teague, and U.S. Pat. No. 7,622,408 to the present inventor, among others. The Teague reference notably discloses a highly-elastic face layer attached to an elastic cushioning backing providing a soft face analogous to the structures in the upper left hand corner of FIG. 1. The remaining references disclose progressively denser and stiffer face layers placing them progressively lower under Teague in FIG. 1. The Scott reference is placed lowest, as it includes a stiff reinforcing sub-layer under the face fabric.
U.S. Pat. No. 5,965,232 to Vinod discloses a highly-reinforced composite floor-covering using a textile face fabric, which is coated with repellent polymers, and attached to a “reinforcing or stabilizing layer” having “good stabilizing properties”. The reinforcing layer is designed “to provide dimensional stability”, to “improve adhesion” and “to provide resistance against puncture and wear”. No mention is made of delamination resistance. An optional cushion layer may be attached to the bottom of the stabilizing layer with permanent or temporary means such as “pressure sensitive” adhesives or mechanical means, such as “hook and loop”. A measure of liquid penetration resistance is achieved by “combining the layers in a manner rendering the composite substantially impervious to liquids”. A preferred reinforcing layer is a highly stable and inextensible “scrim” of “woven or cross-laid glass yarns”. To test resistance to liquid penetration 20 mg of tinted water is dropped from a height of 6 cm onto the composite and “worked-in to produce a uniform stain”. Resistance is judged sufficient if the composite allows no liquid or only a minimum amount of liquid to pass through all the way to the backside of the cushion layer and does not stain or slightly stains a blotting sheet placed underneath within 30 minutes. In addition to this limited resistance to liquid blocking, the presence of a reinforcing layer that is required to increase dimensional stability and puncture and wear resistance will necessarily increase surface stiffness, reduce cushion, and detract from the soft textile hand. Relying upon “the manner of combining” layers to partially or totally block liquid, rather than providing a flexible separate layer that blocks liquids by itself, is also likely to require the selection of particularly stiff reinforcements such as glass, and/or large amounts of adhesives to fill-in pores, excluding the possibility of maintaining a soft and compliant face structure. Vinod is placed adjacent to solid floor-coverings in FIG. 1.
U.S. Pat. No. 7,497,978 by the current inventor discloses needle-punched structures with polymer-rich densified faces that can block liquids at the surface. The stiffness of the face layers places this reference close to solid floor-coverings in FIG. 1.
U.S. Pat. Nos. 7,425,359, 7,431,975, and 8,216,659, all by the current inventor, disclose composite floor-coverings with thin textile face layers attached to a relatively deep cushioning backing. Melt-blown nonwovens or the adhesive layers are given as examples of barrier layers. The surfaces are textured or undulated by embossing with heat and pressure. While these patents disclose improved floor covering products, liquid barrier is considered adequate if a column of water 10 inches high fails to penetrate through to the bottom of the entire composite within 30 minutes. With more rigorous testing, such as water dropped from a height of 1 meter, they exhibit limited and variable barrier performance, partly due to the tendency for the barrier layers under the depressed areas to be thinned-out during the application of laminating/embossing pressure and develop leaks. In FIG. 1 these references are placed above solid floor-coverings because of their relative softness, but below the level of ideal high-impact barrier.
In summary, prior art does not disclose durable textile-faced floor-coverings that could be placed at the upper right-hand corner of FIG. 1, offering a soft textile surface equivalent to commercial or institutional pile cushioning structures, and being simultaneously capable of containing liquids dropped with high impact, for long periods of time, either at the surface or within a thin face layer that can easily be cleaned to avoid bacterial growth.